ethereum · Carsons-Eels · Feb 25, 2026 · Feb 26, 2026 · Feb 26, 2026 · Feb 26, 2026
diff --git a/.gitignore b/.gitignore
@@ -89,3 +89,6 @@ logs/
 env.yaml
 
 site/
+
+# Gas Repricing
+gas_repricing.json
diff --git a/docs/gas_repricing/reference.md b/docs/gas_repricing/reference.md
@@ -0,0 +1,161 @@
+# GasCosts Reference
+
+This page lists the `GasCosts` fields and the opcodes they affect. Use this as
+a reference when creating or editing a `gas_repricing.json` config file to help
+you know which field to override.
+
+For an up-to-date, fork-specific mapping, run:
+
+```bash
+uv run gas-map --fork <ForkName>
+```
+
+## Base Operation Costs
+
+| GasCosts Field | Typical Value | Affected Opcodes |
+|---|---|---|
+| `GAS_VERY_LOW` | 3 | ADD, SUB, CALLDATALOAD, LT, GT, SLT, SGT, EQ, ISZERO, AND, OR, XOR, NOT, BYTE, SHL, SHR, SAR, SIGNEXTEND, PUSH1-PUSH32, DUP1-DUP16, SWAP1-SWAP16, MLOAD, MSTORE, MSTORE8 |
+| `GAS_LOW` | 5 | MUL, DIV, SDIV, MOD, SMOD, CLZ |
+| `GAS_MID` | 8 | ADDMOD, MULMOD, JUMP |
+| `GAS_HIGH` | 10 | JUMPI |
+| `GAS_BASE` | 2 | ADDRESS, ORIGIN, CALLER, CALLVALUE, CALLDATASIZE, CODESIZE, GASPRICE, COINBASE, TIMESTAMP, NUMBER, PREVRANDAO, GASLIMIT, POP, PC, MSIZE, GAS, RETURNDATASIZE, CHAINID, SELFBALANCE, BASEFEE, BLOBBASEFEE |
+| `GAS_JUMPDEST` | 1 | JUMPDEST |
+| `GAS_BLOCK_HASH` | 20 | BLOCKHASH |
+
+## Storage Costs
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_WARM_SLOAD` | 100 | SLOAD when slot is warm |
+| `GAS_COLD_SLOAD` | 2100 | SLOAD when slot is cold |
+| `GAS_STORAGE_SET` | 20000 | SSTORE: setting a slot from zero to non-zero |
+| `GAS_STORAGE_UPDATE` | 2900 | SSTORE: updating existing non-zero slot |
+| `GAS_STORAGE_RESET` | 2900 | SSTORE: resetting to original value |
+
+## Account Access Costs
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_WARM_ACCOUNT_ACCESS` | 100 | BALANCE, EXTCODESIZE, etc. when warm |
+| `GAS_COLD_ACCOUNT_ACCESS` | 2600 | BALANCE, EXTCODESIZE, etc. when cold |
+| `GAS_TX_ACCESS_LIST_ADDRESS` | 2400 | Per address in access list |
+| `GAS_TX_ACCESS_LIST_STORAGE_KEY` | 1900 | Per storage key in access list |
+
+## Exponentiation
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_EXPONENTIATION` | 10 | EXP base cost |
+| `GAS_EXPONENTIATION_PER_BYTE` | 50 | EXP per byte of exponent |
+
+## Memory and Copy
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_MEMORY` | 3 | Memory expansion cost coefficient |
+| `GAS_COPY` | 3 | Per-word copy cost (CALLDATACOPY, CODECOPY, etc.) |
+| `GAS_KECCAK256` | 30 | SHA3 base cost |
+| `GAS_KECCAK256_PER_WORD` | 6 | SHA3 per 32-byte word |
+
+## Logging
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_LOG` | 375 | LOG base cost |
+| `GAS_LOG_DATA_PER_BYTE` | 8 | LOG per byte of data |
+| `GAS_LOG_TOPIC` | 375 | LOG per topic |
+
+## Transaction Costs
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_TX_BASE` | 21000 | Base transaction cost |
+| `GAS_TX_CREATE` | 32000 | Additional cost for contract creation tx |
+| `GAS_TX_DATA_PER_ZERO` | 4 | Per zero byte in tx data |
+| `GAS_TX_DATA_PER_NON_ZERO` | 16 | Per non-zero byte in tx data |
+| `GAS_TX_DATA_TOKEN_STANDARD` | 4 | Token cost per data element |
+| `GAS_TX_DATA_TOKEN_FLOOR` | 0 | Minimum token cost |
+
+## Call and Create
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_CALL_VALUE` | 9000 | Additional cost when transferring value |
+| `GAS_CALL_STIPEND` | 2300 | Gas stipend for calls with value |
+| `GAS_NEW_ACCOUNT` | 25000 | Creating a new account via call |
+| `GAS_CREATE` | 32000 | CREATE opcode base cost |
+| `GAS_CODE_DEPOSIT_PER_BYTE` | 200 | Per byte of deployed code |
+| `GAS_CODE_INIT_PER_WORD` | 2 | Per word of init code (EIP-3860) |
+| `GAS_SELF_DESTRUCT` | 5000 | SELFDESTRUCT base cost |
+
+## Auth (EIP-3074)
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `GAS_AUTH_PER_EMPTY_ACCOUNT` | 25000 | AUTH cost for empty account |
+
+## Precompile Costs
+
+| GasCosts Field | Typical Value | Precompile |
+|---|---|---|
+| `GAS_PRECOMPILE_ECRECOVER` | 3000 | ecRecover (0x01) |
+| `GAS_PRECOMPILE_SHA256_BASE` | 60 | SHA-256 base (0x02) |
+| `GAS_PRECOMPILE_SHA256_PER_WORD` | 12 | SHA-256 per word (0x02) |
+| `GAS_PRECOMPILE_RIPEMD160_BASE` | 600 | RIPEMD-160 base (0x03) |
+| `GAS_PRECOMPILE_RIPEMD160_PER_WORD` | 120 | RIPEMD-160 per word (0x03) |
+| `GAS_PRECOMPILE_IDENTITY_BASE` | 15 | Identity base (0x04) |
+| `GAS_PRECOMPILE_IDENTITY_PER_WORD` | 3 | Identity per word (0x04) |
+| `GAS_PRECOMPILE_ECADD` | 150 | BN256 add (0x06) |
+| `GAS_PRECOMPILE_ECMUL` | 6000 | BN256 mul (0x07) |
+| `GAS_PRECOMPILE_ECPAIRING_BASE` | 45000 | BN256 pairing base (0x08) |
+| `GAS_PRECOMPILE_ECPAIRING_PER_POINT` | 34000 | BN256 pairing per point (0x08) |
+| `GAS_PRECOMPILE_BLAKE2F_BASE` | 0 | BLAKE2 base (0x09) |
+| `GAS_PRECOMPILE_BLAKE2F_PER_ROUND` | 1 | BLAKE2 per round (0x09) |
+| `GAS_PRECOMPILE_POINT_EVALUATION` | 50000 | Point evaluation (0x0a) |
+| `GAS_PRECOMPILE_BLS_G1ADD` | 500 | BLS G1 add (0x0b) |
+| `GAS_PRECOMPILE_BLS_G1MUL` | 12000 | BLS G1 mul (0x0c) |
+| `GAS_PRECOMPILE_BLS_G1MAP` | 5500 | BLS G1 map (0x12) |
+| `GAS_PRECOMPILE_BLS_G2ADD` | 800 | BLS G2 add (0x0d) |
+| `GAS_PRECOMPILE_BLS_G2MUL` | 45000 | BLS G2 mul (0x0e) |
+| `GAS_PRECOMPILE_BLS_G2MAP` | 110000 | BLS G2 map (0x13) |
+| `GAS_PRECOMPILE_BLS_PAIRING_BASE` | 115000 | BLS pairing base (0x11) |
+| `GAS_PRECOMPILE_BLS_PAIRING_PER_PAIR` | 23000 | BLS pairing per pair (0x11) |
+| `GAS_PRECOMPILE_P256VERIFY` | 6900 | P256 verify (0x100) |
+
+## Refund Constants
+
+| GasCosts Field | Typical Value | Notes |
+|---|---|---|
+| `REFUND_STORAGE_CLEAR` | 4800 | Refund for clearing a storage slot |
+| `REFUND_AUTH_PER_EXISTING_ACCOUNT` | 25000 | AUTH refund for existing account |
+
+## Dynamic Opcodes
+
+Some opcodes have dynamic gas costs that depend on multiple `GasCosts` fields
+and runtime context:
+
+| Opcode | Relevant GasCosts Fields | Notes |
+|---|---|---|
+| EXP | `GAS_EXPONENTIATION`, `GAS_EXPONENTIATION_PER_BYTE` | Cost depends on exponent size |
+| SLOAD | `GAS_WARM_SLOAD`, `GAS_COLD_SLOAD` | Warm vs cold access |
+| SSTORE | `GAS_STORAGE_SET`, `GAS_STORAGE_UPDATE`, `GAS_STORAGE_RESET`, `GAS_WARM_SLOAD`, `GAS_COLD_SLOAD` | Complex rules based on original/current/new values |
+| SHA3 | `GAS_KECCAK256`, `GAS_KECCAK256_PER_WORD` | Base + per-word cost |
+| LOG0-LOG4 | `GAS_LOG`, `GAS_LOG_DATA_PER_BYTE`, `GAS_LOG_TOPIC` | Base + data + topics |
+| CALL/CALLCODE | `GAS_WARM_ACCOUNT_ACCESS`, `GAS_COLD_ACCOUNT_ACCESS`, `GAS_CALL_VALUE`, `GAS_NEW_ACCOUNT` | Complex rules based on account state |
+| CREATE/CREATE2 | `GAS_CREATE`, `GAS_CODE_INIT_PER_WORD` | Base + init code cost |
+| BALANCE/EXTCODESIZE | `GAS_WARM_ACCOUNT_ACCESS`, `GAS_COLD_ACCOUNT_ACCESS` | Warm vs cold access |
+| SELFDESTRUCT | `GAS_SELF_DESTRUCT`, `GAS_COLD_ACCOUNT_ACCESS`, `GAS_NEW_ACCOUNT` | Depends on target account state |
+
+## Generating Up-to-Date Mappings
+
+The tables above reflect typical values. Exact values vary by fork.
+
+For the authoritative mapping for a specific fork:
+
+```bash
+# Full mapping
+uv run gas-map --fork Osaka
+
+# Single opcode detail
+uv run gas-map --opcode SLOAD --fork Osaka
+```
diff --git a/docs/gas_repricing/repricing_guide.md b/docs/gas_repricing/repricing_guide.md
@@ -0,0 +1,89 @@
+# Gas Repricing Guide
+
+## What is Gas Repricing?
+
+Gas repricing allows you to override the default gas cost constants for any fork
+without modifying source code. This is useful for:
+
+- Experimenting with alternative gas schedules
+- Testing the impact of proposed EIP gas changes
+- Running "what-if" analyses on existing test suites
+
+## JSON Config Format
+
+Create a JSON file mapping fork names to `GasCosts` field overrides:
+
+```json
+{
+  "Osaka": {
+    "GAS_VERY_LOW": 4,
+    "GAS_COLD_SLOAD": 2200
+  },
+  "Prague": {
+    "GAS_WARM_SLOAD": 150
+  }
+}
+```
+
+Each key is a fork name (e.g., `Osaka`, `Prague`, `Cancun`). Each value is an
+object mapping `GasCosts` field names to their new integer values. Only the
+fields you want to change need to be specified; all others retain their
+defaults.
+
+## Activation
+
+Set the `EELS_GAS_REPRICING_CONFIG` environment variable to the path of your
+JSON config file:
+
+```bash
+export EELS_GAS_REPRICING_CONFIG=./my_gas_repricing.json
+uv run fill tests/osaka/
+```
+
+The repricing config is loaded once (cached) and applied transparently whenever
+`gas_costs()` is called on a fork.
+
+## Finding the Right Field Names
+
+The `GasCosts` dataclass has ~90 fields. To find which field controls a
+particular opcode's gas cost, use the `gas-map` CLI tool:
+
+```bash
+# Show full mapping for a fork
+uv run gas-map --fork Osaka
+
+# Look up a specific opcode
+uv run gas-map --opcode SLOAD
+```
+
+See [GasCosts Reference](reference.md) for a static reference table.
+
+## Example Workflow
+
+1. Identify the opcodes you want to reprice:
+
+    ```bash
+    uv run gas-map --opcode SLOAD
+    ```
+
+    Output shows `GAS_WARM_SLOAD` and `GAS_COLD_SLOAD` are the relevant fields.
+
+2. Create a repricing config:
+
+    ```json
+    {
+      "Osaka": {
+        "GAS_WARM_SLOAD": 150,
+        "GAS_COLD_SLOAD": 2500
+      }
+    }
+    ```
+
+3. Run tests with the new gas schedule:
+
+    ```bash
+    EELS_GAS_REPRICING_CONFIG=./reprice.json uv run fill tests/osaka/
+    ```
+
+4. Compare results against the baseline to see which tests break or change
+   behavior under the new gas schedule.
diff --git a/docs/navigation.md b/docs/navigation.md
@@ -32,6 +32,9 @@
           * [Adding a Blockchain Test](writing_tests/tutorials/blockchain.md)
       * [Opcode Metadata](writing_tests/opcode_metadata.md)
       * [Porting Legacy Tests](writing_tests/porting_legacy_tests.md)
+  * Gas Repricing
+      * [Repricing Guide](gas_repricing/repricing_guide.md)
+      * [GasCosts Reference](gas_repricing/reference.md)
   * [Filling Tests](filling_tests/index.md)
       * [Getting Started](filling_tests/getting_started.md)
       * [Filling Tests at a Prompt](filling_tests/filling_tests_command_line.md)

diff --git a/packages/testing/pyproject.toml b/packages/testing/pyproject.toml
@@ -94,6 +94,7 @@ order_fixtures = "execution_testing.cli.order_fixtures:order_fixtures"
 evm_bytes = "execution_testing.cli.evm_bytes:evm_bytes"
 hasher = "execution_testing.cli.hasher:main"
 eest = "execution_testing.cli.eest.cli:eest"
+gas-map = "execution_testing.cli.eest.commands.gas_map:gas_map"
 fillerconvert = "execution_testing.cli.fillerconvert.fillerconvert:main"
 groupstats = "execution_testing.cli.show_pre_alloc_group_stats:main"
 extract_config = "execution_testing.cli.extract_config:extract_config"

diff --git a/packages/testing/src/execution_testing/cli/eest/cli.py b/packages/testing/src/execution_testing/cli/eest/cli.py
@@ -6,6 +6,7 @@
 import click
 
 from .commands import clean, info
+from .commands.gas_map import gas_map
 from .make.cli import make
 
 
@@ -33,3 +34,4 @@ def eest() -> None:
 eest.add_command(make)
 eest.add_command(clean)
 eest.add_command(info)
+eest.add_command(gas_map, name="gas-map")